* doc/lispref/compile.texi (Native-Compilation Variables): Explain
better what the value -1 of 'native-comp-speed' means.
0 and 3 specify the optimization levels equivalent to the
corresponding compiler @option{-O0}, @option{-O1}, etc.@: command-line
options of the compiler. The value @minus{}1 means disable
-native-compilation; functions and files will be only byte-compiled.
+native-compilation: functions and files will be only byte-compiled;
+however, the @file{*.eln} files will still be produced, they will just
+contain the compiled code in bytecode form.
The default value is 2.
@end defopt